An investigation of the damage to the piles of the apartment building which were suffered from the 1995 Hyogoken-Nanbu earthquake was performed. And by using a part of the piles with little damage which were extracted from the ground, loading test was conducted to clarify the failure mechanism and the lateral force acted on the piles. From the results of the investigation and loading test, the following conclusion were obtained. (1) The piles failed by shear force and then crushed by axial force. (2) The failure pattern of the piles observed in the loading test was the same as that observed in the field. (3) The shear force to cause the failure of pile during the earthquake was estimated to be 360kN.
